Corrugated heat exchange structures



3 Sheets-Sheet 1 Filed May 20,- 1959 INVENTOR. K0437 flzaezav BY 2 WNov. 26, 1963 K. ULBRICHT CORRUGATED HEAT EXCHANGE STRUCTURES 3Sheets-Sheet 2 Filed May 20, 1959 .r 4 w y 7 r m Y B Nov. 26, 1963 K.ULBRICHT 3,111,982

CORRUGATED HEAT EXCHANGE STRUCTURES Filed May 20, 1959 3 Sheets-Sheet 3I N V EN TOR V4 ae/av/r FIG 7 aer FIG.8

United States Patent Fil edl May 20, 1959, Ser. No. 814,635 Claimspriority, application Germany May 24, 1958 3 Claims. (Cl. 165-166) Thepresent invention relates, in general, to heat exchangers and, inparticular, to heat exchangers of the corrugated plate type for fluidmedia.

In plate heat exchan ers which comprise a plurality of plates havingparallel corrugations or grooves to limit the cross sectional areastraversed 'by separate gaseous and/ or liquid media, great diflicultieswere presented when it was desired to obtain the advantages of thecounter-flow principle. These difliculties occurred in the end regionsof the heat exchangers and related to the separate supply and dischargeof the two media being utilized.

As a result, the cross current principle was frequently utilized.However, the cross current principle is less advantageous than thecounterflow principle because of the relatively greater flow resistancesand the irregular temperature diiferences between the two media at thevarious points of the exchangers.

In view of the foregoing, it is an object of the present invention toprovide means obviating these and other disadvantages of prior art heatexchangers.

It is another object of the present invention to provide means in aplate heat exchanger utilizing the advantageous counterflow principlewhile avoiding the previously described diificulties of construction.

It is a further object of the present invention to provide meansconducive to the attainment of a highly economical, efiicient andrelatively simple heat exchanger of the described type, which can bemanufactured and sold at a relatively reduced price.

Briefly described, the present invention comprehends a constructionwherein parallel longitudinal channels are vformed by a stack ofcorrugated plates to provide a central zone for the counter or parallelflow of two separate media, while collecting cross sectional areas areprovided at both ends of the stack for each row of channels, a frontaloutlet and inlet being provided for one medium and a lateral outlet andinlet being provided for the second medium.

Each element of the heat exchanger comprises a pair of plates inopposing mirror relation. Some of the plate elements are provided, atboth sides of the active central zone of the two media, withcorrugations which are offset in a lateral direction so that thecorrugations of adjoining elements are staggered laterally by about halfa division between thecorrugations.

It is possible to construct a corrugated heat exchanger pursuant to thepresent invention in several different forms. Thus, all of the plateelements can be provided, in the end regions thereof, with corrugationswhich are offset, in lateral direction by a quarter of the divisionbetween the corrugations, alternate opposing plate elements being turnedby -180 degrees about their longitudinal axes.

It is possible also to provide each second plate element, in the endregions thereof, with corrugations which are offset, in lateraldirection, by a half division between the corrugations.

The cross sectional flow areas in the end regions of the plate elements,for the medium which is to be supplied and discharged in a transverseflow direction, are terminated by fillers. These fillers likewisepreferably comprise plates which are corrugated in longitudinaldirection and toward the side opposite the inlet and outlet,respectively. These fillers are provided preferably with an inner edgewhich is curved to enhance a favorable deflection of the respectivemedium from a transverse to a longitudinal flow direction and viceversa.

The above and other objects of the invention will become furtherapparent from the following detailed description, reference being madeto the accompanying drawings, showing preferred embodiments of theinvention.

In the drawings which illustrate the best modes presently contemplatedfor carrying out this invention:

FIG. 1 is a side elevation of a corrugated plate element in which thecorrugations are not oifset;

FIG. 1a is an end view of the plate element shown in FIG. 1;

FIG. 2 is a side elevation of -a corrugated plate element in which thecorrugations are laterally offset, pursuant to the present invention;

FIG. 2a is a cross section-a1 view taken on the line B--'B of FIG. 2;

FIG. 2b is across sectional view taken on the line A--A of FIG. 2;

FIG. 3 is a side elevation of a corrugated plate element, as in FIG. 2,having flat longitudinal edges;

FIG. 3a is an end view of the element shown in FIG. 3;

FIG. 4 is a side elevation of a filler;

FIG. 4a is an end view of the filler;

FIGS. 5 and 6 each illustrate a portion of a stack of elements shown incross sectional views corresponding to the sections taken along thelines B-B and A-A, respectively, of FIG. 2.

FIG. 7 is a fragmentary enlarged detail of FIGS. 5 and 6;

FIG. 8 is a schematic view showing the flow paths of the two fluid mediathrough a heat exchanger pursuant to the present invention; and

FIG. 8a is an end view in perspective of a pack of corrugated elementsand fillers embodied in the invention.

Referring now to the drawings in detail, each element 20 of a corrugatedplate heat exchanger 22 (FIGS. 5 and 6), pursuant to the presentinvention, comprises a pair of rectangular plates '1 each formed of thinsheet metal, or other suitable sheet material. The plates oppose eachother in mirror-like manner and are provided with corrugations 3 whichextend longitudinally thereof.

As best seen in FIG. In, this arrangement of the plates defines a seriesof parallel longitudinal channels 2 in each plate element 20. Thecorrugated sections or por tions 2a of the two plates which face eachother, or abut, can be secured together by butt welding, or the like.

This is done only to stiffen or rigidify the two plates and to hold themtogether, since it is not absolutely 3 necessary to separate thechannels within each medium where they are traversed by the same medium.-As a result, the securement of the two plates in each element can belimited to specific points thereof.

After each element 20 is produced from a. pair of plates 1- 1, thecorrugations 3 thereof are laterally offset. This is best shown byelement 20A in FIGS. 2, 2a and 2b. As seen in MG. 2, the central regionor area designated a extends over the major longitudinal extent of theelement 20A. The end regions are designated c-c, and two transitionregions between each end region and the central region a are designatedbb. The corrugations are indicated by the lines 3. These lines extend inlongitudinal direction through the central region a from which theyextend obliquely in lateral direction through each transition region b,at each end of the central region, and they extend again in longitudinaldirection through the end regions.

As a result, and as best seen in FIGS. 2a and b, the channels 2 arestaggered with regard to each other in the regions a and c, in thetransverse direction, it being apparent that each channel is deflectedupwardly from the central region a to the opposite end regions 0, as aresult of its lateral deflection through the transition regions b.

Lln the present instance, each channel is staggered by a quarterdivision of the channel spacing. After the channels are offset, as inFIG. 2, the longitudinal side edges -4 of each element 20A are pressedflat, with the necessary pressure, so that they are forced toward eachother and are devoid of corrugations, as best seen in FIGS. 3 and 3a,wherein the element so treated is designated 20B.

Several plate elements 20B are arranged in pairs as shown at 20B, FIG.6, to form a plate pack 22, and each second or alternate element isturned or rotated by 180 degrees about its longitudinal axis so that thecorrugations of adjacent elements are each offset from the central area:1 toward the end areas c thereof in opposite direction.

This defines in each plate pack 22 separate longitudinal channels 5which are formed only between adjacent central areas a of adjacent plateelements, as best seen in FIG. 5. This arrangement also defines in eachplate pack 22 continuous intervals 6, which are formed from thetransition regions b through the end regions 0 over the entire width ofthe elements. Said continuous intervals 6 are open at both sides 6athereof, as best shown in FIG. 6.

In order to close the intervals 6 in the longitudinal direction of theelements, in the opposite end areas thereof, and in the transversedirection of the elements, toward one side edge thereof, fillers 7(FIGS. 4 and 4a) constituted by corrugated plates, are inserted betweenadjacent plate elements 208, as best shown in FIG. 6. The inner closededge 8 of each filler, facing into an interval or spacing 6, isarcuately ourved so that one of the fluid heat exchange media, which isintroduced into the spaces 6 in a direction to effect transverse flowthrough the plate pack 22, is deflected from a transverse flow directionat the inlet 23 ('FIG. 8) into the longitudinal flow direction of theactive center region a of the plate elements and from the latter theflow is deflected again into a transverse flow direction at the outlet24 (see also FIG. 8a).

This is best shown in FIG. 8, wherein the fluid heat exchange medium Mwhich flows through the intervals or spaces 6 between adjacent plateelements, is designated by the flow line M It will be noted that saidflow line is of general 8 shape, extending from inlet 23 in a directiontransversely of the pack 22, then being deflected, as at 25, by thefillers 7, into a longitudinal flow path, as at 26, from which it isagain deflected, as at 27, by fillers 7, into a transverse flow path 28,for exit at the outlet 24. Instead of having the entrance 23 and theexit 24 at opposite longitudinal side edges of the pack 22, as shown inFIG. 8, they can both be arranged at the same side edge so as to producea U-shaped flow pattern for medium M Consequently, in either case, itwill be apparent that the flow pattern M for the heat exchange medium isa transverse-longitudinal-transverse flow path through the pack 22.

The other medium, which flows through the closed channels 2 and 5, flowsin a substantially straight flow path longitudinally of the pack, froman inlet 32 at one end to an outlet 33 at the other end thereof, asindicated at M in opposition to the 'longitudinal flow path portion 26of path M The flat edges 4 of the elements 208 are welded, as at 29(-FIG. 7), to bars 9 interposed therebetween so as to form closed Walls30-31 at the opposite longitudinal side edges of the pack 22. It will beunderstood that closed wall 31 is interrupted at one end area c to formthe inlet opening 23 and closed wall 30 is interrupted at the oppositeend area c to form the outlet opening 24.

The opposing ends of the pack can also be provided with stiffening walls10 (FIG. 6) if the heat exchanger is to be subjected to high internalpressures. The entire pack can be housed in conventional manner, in apressure-resistant housing that is closed on all sides, for example, bybeing mounted in a pipe.

Instead of offsetting the corrugations 3 by a quarter division orspacing therebetween, it is also within the scope of the presentinvention to provide half the elements with corrugations which extendlongitudinally thereof and to provide the other elements withcorrugations which are offset by half a division in a lateral directionin the regions b and c. In this case it is necessary only that oneelement, which is not offset, alternate with one element which isoffset, so that it is immaterial with what side they oppose each other.

While the present invention has been illustrated and described inconnection with corrugated plates, it is not limited thereto. It iswithin the scope of the present invention to utilize plates providedwith corresponding grooves and strip tubes.

Various changes and modifications may be made without departing from thespirit and scope of the present invention and it is intended that suchobvious changes and modifications be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A heat exchanger comprising at least two pairs of longitudinallyelongated plate elements, a first element comprising a pair ofcorrugated plates disposed in touching contact with their corrugationsdisposed opposite in mirror-like arrangement and including substantiallyhorizontal end corrugated sections and an intermediate oflsetsubstantially horizontal central corrugated section, the respectivecorrugations of said central section being connected to respectivecorrugations of said end sections by oblique sections, a second plateelement substantially similar to said first plate element and disposedin an inverted position adjacent said first plate element with theoutwardly extending corrugated portions in touching contact at said endsections but offset in an opposite manner at said intermediate andcentral sections to define a flow path therebetween, the corrugations ofeach of said pairs of plates defining continuous longitudinal channelsfor the flow of a fluid medium therethrough, the spaces between pairs ofplates defining at said central and intermediate sections a path for theflow of a second fluid medium therethrough, and a filler plate arrangedon each end of said pairs of plates and defining an inlet for directingfluid laterally inwardly to said central section and an outlet fordirecting fluid laterally outwardly from said central section, each ofsaid continuous longitudinal channels being in communication with eachother at locations centrally between and closely adjacent said fillerplates in the region of said inlet and outlet.

2. A heat exchanger according to claim 1, wherein the corrugations inthe intermediate sections of each of said plate elements are bentobliquely about a quarter of a 5 division between corrugations toward anopposite side of said heat exchanger.

3. A heat exchanger according to claim 1, wherein said filler plates aredisposed on opposite sides of each end of said central section andprovide means for directing a 10 fluid medium around one of said fillerplates inside said central section and thence directing said fluidaround the other of said filler plates and for discharge from said heatexchanger.

References Cited in the file of this patent UNITED STATES PATENTSBehringer June 11, 1912 Meveu Dec. 27, 1921 Hume Oct. 9, 1928 ShipmanJune 8, 1943 Burns et al Sept. 4, 1951 Frey et al Oct. 30, 1956 PersonMar. 10, 1959 FOREIGN PATENTS Italy Jan. 25, 1945 Great Britain Mar. 19,1952

1. A HEAT EXCHANGER COMPRISING AT LEAST TWO PAIRS OF LONGITUDINALLYELONGATED PLATE ELEMENTS, A FIRST ELEMENT COMPRISING A PAIR OFCORRUGATED PLATES DISPOSED IN TOUCHING CONTACT WITH THEIR CORRUGATIONSDISPOSED OPPOSITE IN MIRROR-LIKE ARRANGEMENT AND INCLUDING SUBSTANTIALLYHORIZONTAL END CORRUGATED SECTIONS AND AN INTERMEDIATE OFFSETSUBSTANTIALLY HORIZONTAL CENTRAL CORRUGATED SECTION, THE RESPECTIVECORRUGATIONS OF SAID CENTRAL SECTION BEING CONNECTED TO RESPECTIVECORRUGATIONS OF SAID END SECTIONS BY OBLIQUE SECTIONS, A SECOND PLATEELEMENT SUBSTANTIALLY SIMILAR TO SAID FIRST PLATE ELEMENT AND DISPOSEDIN AN INVERTED POSITION ADJACENT SAID FIRST PLATE ELEMENT WITH THEOUTWARDLY EXTENDING CORRUGATED PORTIONS IN TOUCHING CONTACT AT SAID ENDSECTIONS BUT OFFSET IN AN OPPOSITE MANNER AT SAID INTERMEDIATE ANDCENTRAL SECTIONS TO DEFINE A FLOW